ShapeDetection: use mojom::Bitmap for mojo interface.

content/public/android/java/src/org/chromium/content/browser/shapedetection/FaceDetectionImpl.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.content.browser.shapedetection;
 
 import android.graphics.Bitmap;
 import android.graphics.PointF;
 import android.media.FaceDetector;
 import android.media.FaceDetector.Face;
 
 import org.chromium.base.Log;
 import org.chromium.gfx.mojom.RectF;
 import org.chromium.mojo.system.MojoException;
-import org.chromium.mojo.system.SharedBufferHandle;
-import org.chromium.mojo.system.SharedBufferHandle.MapFlags;
 import org.chromium.shape_detection.mojom.FaceDetection;
 import org.chromium.shape_detection.mojom.FaceDetectionResult;
 import org.chromium.shape_detection.mojom.FaceDetectorOptions;
 
 import java.nio.ByteBuffer;
 
 /**
  * Android implementation of the FaceDetection service defined in
  * services/shape_detection/public/interfaces/facedetection.mojom
  */
 public class FaceDetectionImpl implements FaceDetection {
     private static final String TAG = "FaceDetectionImpl";
     private static final int MAX_FACES = 32;
     private final boolean mFastMode;
     private final int mMaxFaces;
 
     FaceDetectionImpl(FaceDetectorOptions options) {
         mFastMode = options.fastMode;
         mMaxFaces = Math.min(options.maxDetectedFaces, MAX_FACES);
     }
 
     @Override
-    public void detect(
-            SharedBufferHandle frameData, int width, int height, DetectResponse callback) {
+    public void detect(org.chromium.skia.mojom.Bitmap bitmapData, DetectResponse callback) {
+        int width = bitmapData.width;
+        int height = bitmapData.height;
         final long numPixels = (long) width * height;
         // TODO(xianglu): https://crbug.com/670028 homogeneize overflow checking.
-        if (!frameData.isValid() || width <= 0 || height <= 0 || numPixels > (Long.MAX_VALUE / 4)) {
+        if (bitmapData.pixelData == null || width <= 0 || height <= 0
+                || numPixels > (Long.MAX_VALUE / 4)) {
             Log.d(TAG, "Invalid argument(s).");
             callback.call(new FaceDetectionResult());
             return;
         }
 
-        ByteBuffer imageBuffer = frameData.map(0, numPixels * 4, MapFlags.none());
+        ByteBuffer imageBuffer = ByteBuffer.wrap(bitmapData.pixelData);
         if (imageBuffer.capacity() <= 0) {
-            Log.d(TAG, "Failed to map from SharedBufferHandle.");
+            Log.d(TAG, "Failed to wrap from Bitmap.");
             callback.call(new FaceDetectionResult());
             return;
         }
 
         Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
 
         // An int array is needed to construct a Bitmap. However the Bytebuffer
         // we get from |sharedBufferHandle| is directly allocated and does not
         // have a supporting array. Therefore we need to copy from |imageBuffer|
         // to create this intermediate Bitmap.
         // TODO(xianglu): Consider worker pool as appropriate threads.

[mcasas, 2017/01/19 18:09:48]

Please update this comment.

         // http://crbug.com/655814
         bitmap.copyPixelsFromBuffer(imageBuffer);

[mcasas, 2017/01/19 18:09:48]

Here you're copying |imageBuffer| into |bitmap| which is initialized
as Bitmap.Config.ARGB_8888 in l.56, but that's only correct if
bitmapData.colorType is ARGB_8888 itself.   You need to consider 
this here and in the other .java detector implementations.

OTOH if you read l.66, findFaces() works in RGB_565, so if the 
incoming |bitmapData| is in that format, we can skip the intermediate
imageBuffer --> bitmap --> unpremultipliedBitmap step, and
go directly imageBuffer --> unpremultipliedBitmap, assuming 
|imageBuffer| is directly accessible. 

 
         // A Bitmap must be in 565 format for findFaces() to work. See
         // http://androidxref.com/7.0.0_r1/xref/frameworks/base/media/java/android/media/FaceDetector.java#124
         //
         // It turns out that FaceDetector is not able to detect correctly if
         // simply using pixmap.setConfig(). The reason might be that findFaces()
         // needs non-premultiplied ARGB arrangement, while the alpha type in the
         // original image is premultiplied. We can use getPixels() which does
         // the unmultiplication while copying to a new array. See
         // http://androidxref.com/7.0.0_r1/xref/frameworks/base/graphics/java/android/graphics/Bitmap.java#538
@@ skipping 29 matching lines @@
     }
 
     @Override
     public void close() {}
 
     @Override
     public void onConnectionError(MojoException e) {
         close();
     }
 }